This invention relates to solid lubricants for lubricating movable machine parts.
Operation of bearings, gears, cams and other mechanical components in conventional gas turbine and automotive engines are generally limited to temperatures of about 350.degree. to 400.degree. F., because the conventional liquid lubricants used in the engines usually thermally decompose above about 400.degree. F. Advanced turbine engines and other high temperature engine types (stirling, adiabatic, diesel) may require bearing operation above 1000.degree. F. and therefore require alternate lubrication systems. Conventional solid lubricants such as molybdenum disulfide (MoS.sub.2) and tungsten disulfide (WS.sub.2) are useful to about 800.degree. F. and may be used in coating or powder form. Advanced solid lubricants such as cesium oxythiotungstenate (Cs.sub.2 WOS.sub.3) and other complex chalcogenide lubricants, either in coating or in powder form, have been shown. to perform well at temperatures above 1200.degree. F. However, specialized equipment for pretreating bearing surfaces and applying a lubricant coating thereon, or for delivering the powder form to the bearing surfaces, in the utilization of advanced lubricants in either coating or powder form may be required.
I have discovered that substituted biphenyl sulfones are useful as lubricants in the temperature range of up to about 750.degree. F.
Accordingly, it is an object of the present invention to provide novel lubricating materials.
Other objects and advantages of the present invention will be apparent to those skilled in the art.